Riding
by Fireside Commulist
Summary: Phineas tests out a new VR system with Isabella, one that can bring out one's desires. One of Isabella's biggest fantasies about her boyfriend is forced to reveal itself. Rated M for sex.


Isabella awakened on a patch of grass. It felt and smelt as fresh as the real thing, even though she knew it was all virtual reality. She looked up at the sky, and saw an explosion of colour. It was as if the deepest parts of space were brought to her doorstep. Awestruck, she stood up and walked to her partner.

'Okay, Phineas, it's an awesome VR system. What's the special part?' Isabella said.

'It's VR that's hyper realistic. Not only does it feel like actual reality, but it allows you do to anything you want regardless of whether it's physically possible,' Phineas said.

'This isn't anything new, but you really wanted me to come experience this. There's more to it, isn't there?'

Phineas smiled. 'Okay, it's not so much the actual VR, but why I'm using it. I'm experimenting with ideas in case circumstances require us to be apart. Portal setups can be quite costly and inefficient, so I'm working on trying to create a VR system designed specifically so we can connect and be together like it's the real thing, even as we're apart.'

'Phineas, that's so sweet of you.' Isabella wrapped her arms around and kissed her partner. 'I mean, it wouldn't surprise me given you and Ferb already have your holo-chats, but you went even further just for me?'

Phineas held Isabella. 'Why wouldn't I? I can't exactly cuddle and kiss a hologram.'

Isabella let out a small chuckle. 'So, what do you propose we do here?'

'Did I mention that this is heavily influenced by our subconscious, making it kind of a dreamscape? You can do anything you want, but what we already find here is determined by our unconscious.'

Isabella slowed down her voice. 'But you still said we can do anything, right?'

'I did. Do you have ideas, or do you want to see what happens?' Phineas's eyes lit up.

Isabella smirked. 'I'd like to suggest a direction of my own.'

Isabella pulled Phineas down to kiss him again. Phineas chose not to resist, letting his girlfriend press her mouth against his. Isabella soon slowed down her kisses, moving to cuddle Phineas. Except Phineas suddenly felt bigger. Isabella shuffled back to see that Phineas somehow took on a form that she knew all too well.

'Phineas, did you just turn yourself into a centaur?' Isabella's face flushed red.

Phineas looked at his sturdy new equestrian lower half, brown and covered in fur. 'No? I tested everything out to make sure something like this wouldn't happen. Let me see if I can fix it.'

Within seconds, Phineas turned himself back into his regular form. He looked at himself, surprised.

'That was much easier to fix than I thought it would be,' Phineas said.

Isabella forced a laugh as she was sweating, her skin still bright red. 'Well that sure is a relief, huh? Let's hope it doesn't happen again. Let's go for a walk through this place.'

As they started walking, Phineas held Isabella's hand. 'Isabella, are you okay? Your body temperature seems to have risen a lot.'

'Oh, it's nothing, it's nothing. I'm fine, let's keep walking.'

They traversed a few small hills of grass, looking at the various flowers the VR presented to them. Phineas and Isabella both took the chance to pick some up smell them, and much like the grass, it was as if they were real.

Isabella picked up what appeared to be a rose and went to give it to Phineas, however she was greeted by a familiar face. Or rather, familiar appearance.

Isabella stifled a scream, clasping her mouth shut. 'Phineas, you're a centaur again.'

Phineas looked down on his body. 'Wow, I am. You have to admit, this is kinda cool, even if it's not my intent at all. Unless… I subconsciously want to be one, given that our subconscious influences this environment to provide what we desire.'

Isabella's face shot red. 'Oh wow, that's a, uh, interesting thought. It must clearly be that. Say, why do you have jeans on your hind legs?'

Phineas turned around. 'Wow, that is weird. Those weren't there before. Hang on, if they're jeans and meant to be for my legs, shouldn't they be designed to fit all four of them instead of my back ones?'

'Just change back to normal before… uh… I lost my train of thought.' Isabella started to breathe heavily.

Phineas turned back into his regular form. 'Isabella, are you sure you're okay?'

Isabella attempted to slow her breathing. 'I'm fine. I'm fine. I'm totally fine. I promise.'

Phineas held her hands. 'Look, if something's bothering you, don't be afraid to tell me. Also, that's a nice outfit you have there. It's so cute.'

Isabella looked down her body and saw she was wearing a violet and pink dress. The skirt was short and sparkly, and her midriff was exposed. The top half of the dress looked like a corset, covering the main body but everything from her cleavage above was exposed. Her hind arms had sleeves on them, and were connected to the main dress through translucent violet ribbons. Most curiously, not only was she now wearing her trademark bow, but from her back she had large, translucent butterfly style wings.

Isabella smiled. 'Okay, I didn't do this, but I love it. I look so pretty in this! You said you found it cute… was this your doing, Phineas?'

Phineas chuckled to himself and slightly blushed. 'Well, to be honest, I always wanted to see you in a form resembling a fairy. You know I love it when you act cute, but I always wondered what it would be like if you had an appearance that pretty much embodies cute.'

Isabella hovered over to Phineas, her eyes growing sultry. She kissed him on the nose, and after a brief moment of catatonia, Phineas responded by grabbing her by the arms and pulling her down to kiss her back.

Isabella flew into Phineas's arms to continue kissing him, her body elevating with him. She attempted to wrap her legs around Phineas, but felt a large, furry body instead. Isabella pulled away to see that Phineas was a centaur again, and screamed. She flew away, only for Phineas to run after her.

Phineas yelled to Isabella as he galloped at top speed. 'Isabella, what's wrong?'

Isabella growled. 'Nothing is wrong, Phineas. Just leave me alone!'

'Isabella, I'm not stupid. Something's bothering you. Can we at least talk? I hate running with these centaur jeans anyway.'

Isabella sighted a small pond. 'I said I'm fine. Can we just look at this pond?'

'Only if you tell me what's bothering you.'

Isabella looked down to see Phineas pleading to her with his eyes. 'Ugh, fine. But don't be surprised if this gets weird.'

Isabella landed by the pond, and Phineas sat beside her, still in his centaur form. He rested his arm on her shoulder, only for her to hug him back and cry into his shirt.

Phineas stroked his girlfriend's hair. 'Isabella, you know you can tell me anything. What's got you so scared here?'

Isabella sniffled. 'Phineas, I know I'm going to sound crazy for this, but… your device is working exactly as intended. I just don't know how to handle it.'

'What do you mean?'

Isabella pulled away from his body. 'Phineas, this whole centaur thing. It's not a glitch or some hidden subconscious desire. It's from my own _conscious_ desires.'

'There's nothing wrong with that. What's bothering you so much if you want me as a centaur?'

Isabella looked into the reflection of the pond. 'You remember Phineasland, right?'

'Yeah? How you used to always daydream and have fantasies about me before we got together?'

'Yeah. Well, one of the biggest fantasies I had was you becoming a… centaur.' Isabella's voice grew increasingly hesitant.

Phineas removed his shirt and inspected himself. 'Wow. You could've told me and I could've turned myself into one for a day to give you rides, that would've been so fun. Not to mention a great bonding experience.'

Isabella turned to Phineas. 'How are you so okay with something so weird? How can you suggest that without any hesitation? I find you attractive as a mythical horse man. It's so weird and messed up. I always loved horses and all that, but this? Why is a centaur attractive to me? I don't get it.'

'Does it have to make sense, though? Sometimes we just like things, or in this case, are attracted to them. Isabella, I don't just find your fairy look cute; I find it really sexy. Your cuteness makes you even sexier to me.'

'At least I look human though. Strip off these wings and I'd just be a woman in a pretty dress. You… you're a human body on a horse. How is that not so much weirder? Does it mean I want to fuck horses? I don't want to be a horse fucker, Phineas!'

Phineas drew Isabella towards his chest, allowing her to feel the more defined muscles of his centaur form. 'Isabella, think about it. If I became a centaur in real life, I'd still be the same person you fell in love with, right?'

Isabella's voice calmed. 'I suppose… I mean, you would. But… you'd part horse. How could people just accept that? Well maybe we'd get away with it in Danville, but still, how?'

Phineas's eyes widened. 'Wait, is this what this is really about? Are you just worried about what other people would think of you?'

'Phineas, I'm not someone who'd just go to someone and say "oh hey, I daydream about my boyfriend as a centaur and fucking him like that".'

'But you don't go around telling people about your private sexual life like that, right? I mean, I don't intend to tell people about my sexual life. Isabella, you're fine. You don't need to share this with anyone but me.'

'But… but… ugh. It's just weird, okay? Like, weirder than normal weird.'

Phineas lifted Isabella's chin to face him. 'That isn't a bad thing though. The weirdest things can sometimes be the most fun. Maybe you're just ashamed of your younger self and what you used to dream up?'

Isabella's eyes darted sideways. 'But it's not just me before our relationship. I still have thoughts about how hot it would be to be fucked by you as a centaur. It's just so strange, why are you even okay with it?'

'Because I'm all about seizing the day and trying out new things. If it means being a centaur to give my girlfriend sexual gratification, then I say go for it. It sounds really fun, anyway.'

'You know, I keep forgetting how weird you yourself can be, Phineas. I need to stop being so surprised at you being okay with the strangest things.' Isabella grew a smile and gave a soft chuckle.

'You're worried too much about being the ideal girl for me. The ideal girl for me is the person you truly are, not a more normal, bland and presentable version of yourself.'

Isabella let out a soft gasp. 'Wow, Phineas. You really would love me no matter how strange the things I like and want would get? Also, your jeans are gone.'

Phineas turned around to see his jeans indeed disappeared. 'Huh, that's weird. But I mean, of course I would. You always stood out to me, yourself. I've never known anyone so versatile, so adaptable, so enthusiastic about the world around her. It makes me wonder why I didn't realise how much I loved you sooner.'

Isabella and Phineas went silent, with Isabella tightening her arms and legs around Phineas. She used her feet to reach for his fur, and the softness of it prompted her to rub her them in it. Phineas responded by cooing to her and tracing his hands over her body, with Isabella shivering with pleasure as he gently touched her wings.

Phineas then initiated a kiss with Isabella, who tightened her grip as she reciprocated. Her wings fluttered as she grew more passionate, moaning between kisses. Phineas slipped one of her breasts out of her outfit and started to fondle it, which caused Isabella to moan even louder.

As Phineas exposed her other breast and began playing with it, Isabella's breathing intensified and she gripped on to Phineas's body. Next thing she knew, she was carrying them both into the air like it was nothing.

'You know, I bet you'd be strong enough to carry me in reality too.' Phineas smirked.

Isabella's face went sultry. 'Oh really, now? Is that an invitation?'

'If you want it to be. Your strength is part of what makes you so cute, after all.'

After Isabella giggled, Phineas continued to feel across Isabella's body as he kissed her. He slowly removed the items of clothing she still had until all that was left was her wings, only for Isabella to shed them too.

Phineas took a moment to observe his surroundings, and eyes widened as he saw how high they were. However, neither of them fell. Isabella continued to hold him and rubbed across his body.

'So, uh, do you want to try this up here?' Phineas said.

Isabella's voice lowered. 'Yes, yes I do. If this is my first time fucking a centaur, I'll make it as special as possible.'

Isabella then floated up to Phineas to give him a slow, passionate kiss. She rubbed his body and then went under him to let herself be penetrated. As Phineas's large centaur penis entered Isabella, she shuddered and grinned.

Isabella put all of the energy she had in her body to fucking Phineas in this form. Phineas found he had to bend his body to help and feel her, and in response Isabella found herself stretching to reach him.

Isabella allowed her body to grow elastic to the point where Phineas's cock could fully enter her. Isabella looked down for a moment to see that it was so large it was causing massive distension to the point where you could see a phallic shape form inside from where she was penetrated.

Isabella was moaning to tears. 'Phineas… Phineas…'

'Isabella, are you okay?' Phineas laid kisses on his girlfriend as their bodies twisted into each other.

'I… I love this so much… I love you so much…' Isabella's voice faded as she gave into her desires.

As Phineas realised his deep penetration was already causing an orgasmic effect on his girlfriend, he wrapped himself even further around her. Isabella's arms and legs grew to the point where they wrapped around his entire body. Eventually, it was too much for either to hold in.

'Isabella, get ready!' Phineas yelled as he let out the largest ejaculation he had in his entire life, the hot, supercharged semen tickling Isabella's insides for more pleasure.

Isabella yelled Phineas's name one last time before having her own climax. The lovers then descended back to the ground, and both were in their normal forms. Well, except for one thing.

Isabella looked to see her head buried into his chest, literally. 'Wait, Phineas… I feel like I'm inside you.'

Phineas looked down on her. 'Isabella, we just cam- oh, I see what you mean. We're clipping into each other. Must be another glitch, I don't know if this simulation can handle such strong emotions like those during sex.'

'If it's a mistake, then I don't want it to be. I like feeling closer than physically possible.'

'When you put it that way, let's spend some more time like this. Feeling you inside me feels so… I don't know how to describe it.'

'I bet it's love. You feel love with me in a new way through this.'

Phineas smiled and ghosted his hand through Isabella's hair. 'Yeah, probably.'

Phineas and Isabella pushed even more of their bodies into each other to experience the clipping sensation. The lovers sighed and relaxed, lying into each other for a while.

Eventually, Phineas and Isabella decided it was time to exit the VR simulation. As they did so, they leaned into each other one last time to feel the clipping. The both of them found themselves waking up on their bed.

'Wow, there's no signs of anything on my body at all, but it's like I still feel everything,' Isabella said.

Phineas held Isabella's hands. 'That's what I hoped. I know it got weirder than just me as a centaur, but you still had fun, right?'

'Of course, love. Can we do more of this? Can we do more centaur stuff?'

Phineas eyes sparked open. 'Oh, Isabella, you should know me by now. You know how I said it would've been cool if I could really transform myself into one?'

Isabella only responded with a massive grin and incoherent giggling.

'Yeah, I thought you'd love it. I mean, I meant to save VR specifically for when we're apart and can't reach each other, right?'

Isabella still couldn't speak. Phineas responded with a kiss to her lips.

'I know you're excited, but I'm tired and I wanna sleep now. I promise I'll do this for you by the end of the week. But you know, maybe we can have something nice and relaxing before we fall asleep, like classic lovemaking.'

Isabella sighed. 'Phineas, what did I do to deserve you?'

Isabella kissed her boyfriend back, and within seconds they were already undressing and tenderly across each other's bodies. Then the lights went out, and they were back to making love like it was nothing.


End file.
